Connection systems for subsea pipelines have major importance in the oil industry, especially at offshore area. Necessity to transport fluids in great depths connecting oil wells to the platforms, two or more subsea equipment or transport directly to the offshore, for example, requires kilometers of pipelines of fluid transport and, subsequently, of equipment connecting said pipelines.
The connection equipment (or termination) are assembled at intermediate points or at the end of pipelines and are typically composed of a metal frame for foundation on sea soil, control and fluid block valves, sections of intermediate pipelines and spindles for connection with other equipment, for fluid import and export, as well as injection or service on the well. In addition, a further frame is required, partially independent of foundation frame, which has the function of fix these components and to withstand the stresses generated by the weight of line during installation, keeping the components pressurized which have contact with the production or injection fluid out of load line during installation.
An example of typical subsea architecture diagram for connection between manifold for four wells and Pipeline End Termination (PLET) is shown on FIG. 1 (state of art). This diagram illustrates a production manifold which is used to collect fluids from the wells, exporting them to line connection equipment, such as a PLET by means of a jumper or spool.
A typical schematic view of a state of art manifold, spool or jumper, and PLET is the shown in FIG. 1. The manifold comprising fluid import/export spindles (1) is connect to the header (3) by means of block valve (2) to each Wet Christmas Tree (WCT) branch and an additional valve (4) for the header (3). This header (3) of the manifold, by a spindle, is connected to a jumper or spool (5)—rigid and flexible pipelines containing a vertical or horizontal crimp at each of its ends—by subsea connectors (6), which need to be locked or unlocked with the use of remotely operated subsea vehicles and still making the seal between equipment to avoid leaks. The jumper or spool (5), in turn, is connected to the PLET spindle, which has a block valve (7) to performing subsea line isolation (8) welded to the PLET. All these equipment have to be assembled on a frame (9) resistant enough to withstand all stresses from the lines, as indicated in FIG. 2. FIGS. 2 and 3 illustrate perspective and front cut views, respectively, the frame (9) of a typical PLET and detail of line supporting beam (10), as usually practice by the state of art.
The architecture illustrates in FIG. 1 then essentially needs a manifold, jumper or spool, PLET, six stop valves, which can varies as the manifold application or field need, and additionally more two connectors. It occurs that in operational practice, said state of arte architecture presents two potential points of undesirable fluid leak, which are the said connectors.
In addition, it is still necessary a plurality of other components, besides essentials, such as welding seams, secondary valves and components for seal that require a structural stress to withstand them. Other important factor is the particularity of subsea environment, whose increasing depth exert great pressure on the lines, making them increasingly heavy and demanding more of the equipment installed.
FIG. 4 shows a typical four wells system, where a manifold is interconnected to four Wet Christmas Trees (WCT), a jumper or spool connected to conventional PLET equipment. The production trees are linked to the manifold, the latter of which is intended to equalize the production from the wells. PLET is used to interconnect the manifold with the production lines. At the conventional frame of manifold and installation methods of conventional subsea equipment, it is not possible to realize a direct interconnection of line with said manifold. Thus, PLET it is necessary to perform the descent of production line, usually measuring kilometers and weighting on order of more than 600 tons, responsible for outflow of production and in order to be possible to make interconnection with manifold. In other words, at the traditional methods there is no possibility to make the direct connection of these production lines with manifold, thus needing PLET.
Furthermore, in traditional oil drilling systems, a plurality of other components, other than the above-mentioned essentials, such as weld beads, secondary valves, and seal components are required which require significant structural effort to support them. Another important factor is the particularity of the subsea environment, whose depth, increasing, exerts great pressure on the lines making them increasingly heavy and demanding more of the equipment installed.
As is known, subsea equipment typically have a very robust structure, ie, high dimensions and weight to withstand underwater conditions, where pressure and corrosion resistance requirements are severe, as well as extreme loads occurring during Installation of the same. When manufacturing a PLET or PLEM (Pipeline End Manifold) type of equipment, it is first necessary to develop the project design and then proceed with the manufacture of pressurized elements such as valves, pipes and ducts. Once these elements are manufactured, they must be integrated with the metallic interface structure with sea soil, such as foundation, balconies or mudmat, as well as with the supporting metal beams for these components necessary for the installation of the equipment in the soil subsea. The integration of these components requires critical weld strands, that is, complex processes since welding requires both special preparation and qualification, which are costly and time consuming processes. Currently, the integration process requires at least four months for the manufacturing and delivery process of PLET-type equipment.
PLET-type equipment is then connected to a flexible or rigid pipe through which the oil/gas production flows or the water/gas is injected into the WCTs installed in the wells. This tube in an subsea field extends for kilometers of distances, for example, 10 km, representing a typical weight of about 600 tons. When installing PLET-type equipment, this pipe will be connected to the equipment, as shown in FIG. 3. However, it is required that the load line from the loads carried by that tube does not pass through the pressurized elements, such as valves, pipes and ducts and, in order to comply with this requirement, a structural support beam (10) of the line to support this weight, thereby protecting said pressurized elements which are in contact with the production or injection fluid. Said structural framework is shown in FIGS. 2 and 3.
The support structure, including said supporting beam of the line (10), adds to the equipment a very high dimension and weight requiring special vessels for its installation. As the PLET design is not standardized and has support structures that change as needed, special vessels and support logistics for the installation are changed on a case-by-case basis, making the subsea field projects more expensive and increasing the actual time of its installation.
All of these factors contribute significantly to delaying the subsea production process, increasing costs related to design, fabrication, testing, transportation, mechanical integration, and installation of equipment in the seabed.
Currently there are in the market efforts and technological developments in an attempt to reduce the costs of the equipment for production and oil drilling. In this sense, an effort has been made in researches and solutions carried out in the equipment itself as well as solutions that make feasible the optimization of the configuration of the subsea field, but to date there is no adequate solution for this technological demand.
The present invention advantageously, robustly and efficiently solves all of the above-mentioned drawbacks of the prior art, in addition to others arising and not mentioned herein.